Battery advice

[Traceyi]

Hi
I’ve just bought a second hand Halfords carerra ladies folding cross city e electric bike which needs a new battery not realising how expensive they are till I called Halfords I was looking at a rebuild with maybe a bit more amp. As I’m new to all this is there anyone who can tell me where to go anywhere cheaper than Halfords or give advice would be much appreciated.

 

[vfr400]

You can buy them much cheaper from Aliexpress. Can you take it out and show us a photo. also measure the length because there are different size versions.

Another option is to get it re-celled, which would be about £200.

This one looks very similar - nice and cheap at £140 with a spare charger, but you have to confirm that it's the same size:

Green Cell® E-Bike Battery 36V 7.8Ah Li-Ion Frame with Charger

Green Cell® E-Bike Battery 36V 7.8Ah Li-Ion Electric Bicycle Pedelec Frame-Type with Charger immediate dispatch, 12 month warranty, efficient cells

batteryempire.co.uk

Before spending any money, are you absolutely sure that it only needs a new battery?

 

[Traceyi]

Well the owners told me they bought it new used it very little then put away in garage was unaware you had to keep the charge topped up. I’ll attach photo for you to check for same type

 

[sjpt]

If the battery is dead from being stored too long uncharged you may be able to revive it by putting on charge for a long time. I understand that there are also special chargers that can work when regular ones won't, but not so easy to come by. Most people are unaware of the store uncharged problems; manuals and bike shops don't usually mention it.

Also, you may be able to fix it by opening it up and charging the different cell groups separately, but that is quite technical. Don't try unless you are confident; ask here first and one of the more knowledgeable members will guide you.

If you go for the recell option mentioned above they will almost certainly be able to use larger capacity cells than the original, so you'll get a better battery than the original when new.

 

[Nealh]

Well the owners told me they bought it new used it very little then put away in garage was unaware you had to keep the charge topped up. I’ll attach photo for you to check for same type

Do you have or have access to meter, if not a cheap DVM can be bought on ebay. A voltage reading might be useful to start with. Some batteries have a sleep mode one can try pressing the on/off switch for about 10 -30 seconds.

 

[Traceyi]

If the battery is dead from being stored too long uncharged you may be able to revive it by putting on charge for a long time. I understand that there are also special chargers that can work when regular ones won't, but not so easy to come by. Most people are unaware of the store uncharged problems; manuals and bike shops don't usually mention it.

Also, you may be able to fix it by opening it up and charging the different cell groups separately, but that is quite technical. Don't try unless you are confident; ask here first and one of the more knowledgeable members will guide you.

If you go for the recell option mentioned above they will almost certainly be able to use larger capacity cells than the original, so you'll get a better battery than the original when new.

It’s such a shame as I know the battery has hardly been used I wish I could revive it. The option of recell comes up expensive where I asked for a price? More than getting new from Halfords.

 

[Traceyi]

Do you have or have access to meter, if not a cheap DVM can be bought on ebay. A voltage reading might be useful to start with. Some batteries have a sleep mode one can try pressing the on/off switch for about 10 -30 seconds.

I’m not sure what type of meter you talking about if it’s voltage type then I haven’t got one maybe good idea to get one then but the owners said they used bike up and down drive then stored it unaware they had to keep charge going as they weren’t told but phoned Halfords when I was going to collect as it had not charged. Sorry I’m new to all this so all a bit unknown to me but thanks for your help.

 

[Nealh]

With out a voltage meter there's not a lot we can help with if the real time voltage isn't known.
Do you not have a relative or friend who can help out ?
We can guide you in to what needs doing/checking with quite easy how and where.
A part from the cost of a meter about £5 - £10 it cost's nothing to carry out the checks.

 

[Nealh]

Have you tried the long press of the on/off switch as I mentioned ?

I expect what has occurred is due to no use one of the cell groups has dropped to about 3v and the batteries internal BMS will not switch the charge mosfets this in turn doesn't allow the charger to supply current and begin charging.
With a meter and the battery opened simple voltage checks can be made to determine where the fault is and if it can be rectified. If the fault can be rectified then the battery can then be charged and work as normal.

 

[Nealh]

Which part of the country do you live in, any where near West Sx ?

 

[Traceyi]

Which part of the country do you live in, any where near West Sx ?

No swansea wales

 

[Fat Rat]

Welcome to the site

 

[Traceyi]

Welcome to the site

Thank you